Answer: 5 1/10
Solution:
2/5-[-4 7/10]
2/5-[-(4*10+7)/10]
2/5-[-(40+7)/10]
2/5-[-47/10]
2/5+47/10
2*2/(5*2)+47/10
4/10+47/10
(4+47)/10
51/10
(50+1)/10
50/10+1/10
5 1/10
